The present invention relates to light-measuring systems.
Thus, the present invention relates to systems which may be used as exposure meters in connection with photography, such exposure meters either forming separate units or being incorporated into and forming part of a camera.
As is well known, areas which are to be photographed often are unevenly illuminated so that part of the area to be photographed has a maximum brightness while another part has a minimum brightness. At the present time in order to scan such areas with conventional light-measuring systems it is necessary for the operator to swing or otherwise move the light-responsive structure so that it will pick up the light of different brightness coming from different parts of a given area which is to be photographed. Such operations represent a considerable inconvenience not only because of the scanning movement which the operator must carry out but also because of the time required for such an operation and the necessity of the operator to detect where the maximum and/or minimum brightness of a given scene are located.
It has already been proposed to avoid the above drawbacks by providing a system which can remain stationary while detecting maximum and/or minimum brightness of a given area which is to be photographed, so that it becomes possible to determine statically the maximum and/or minimum brightness or the range of brightness therebetween.
It is well known that in ordinary photography an exposure must be well defined within a density curve of the particular film which is being exposed so that in order to obtain a photograph of good tone, consideration must be given to the relationship between the range of brightness of the object to be photographed and the density curve of the film.
Up to the present time there has been no satisfactory system for taking into consideration the variable brightness of a given area which is to be photographed as it relates to the density curve of the film which is exposed. Some extremely careful photographers who are particularly concerned with these factors use the so-called spot-exposure meters for determining the brightness of selected parts of the area to be photographed and then provide suitable camera adjustments taking into consideration readings from the different parts of the area which is to be photographed in connection with the density curve of the film. However, these operations are extremely inconvenient in that it is essential for the operator, as when the light-measuring system is incorporated into a camera, to view different parts of the scene or area which is to be photographed in the viewfinder taking into consideration the different brightness values which are provided in this way and then providing suitable camera settings. Such inconvenient and time-consuming operations may give satisfactory results with respect to a stationary object which is to be photographed, assuming that the lighting conditions remain substantially unchanged long enough to provide for a meaningful reading of the different light intensities from different parts of the object, but of course when photographing a moving object it is impossible to carry out these careful operations and often the opportunity for making a highly desirable photograph is missed because of the tedious operations presently required as set forth above.